Duplicate Emails

Hi,
We have recently installed a new Zimbra Appliance 8.04. We also installed Zextras 1.88 on the server. I have been migrating accounts from our Zimbra 6.04 to the new server. Everything has been going well but now We have a few accounts that are receiving duplicate email messages and some are getting duplicate calendar entries as well.

Have you performed the migration with ZeXtras Suite/ ZeXtras Migration Tool or with Zimbra Wiki guide?
As far as I know you can't use Zextras to perform a migration from a Zimbra 6.04 (required at least 6.07)
If you didn't use Zextras to migrate the server you can remove it from the problem search.